/*
 * Copyright (c) 2014, marco.tamburelli@gmail.com
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met: 
 * 
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer. 
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution. 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.omorphdb.core.test.mock;

import static org.omorphdb.core.value.ValueConstants._BYTE;
import static org.omorphdb.core.value.ValueConstants._INT;
import static org.omorphdb.core.value.ValueConstants._SHORT;

import org.omorphdb.core.exception.CorruptedStorageException;
import org.omorphdb.core.index.hash.HashFunction;
import org.omorphdb.core.index.hash.HashFunctionFactory;
import org.omorphdb.core.value.ValueType;

public class HashFunctionFactoryMock extends HashFunctionFactory<String>
{
	private static final int INITIAL_SLOT_COUNT = ValueForMock.values().length / 2;

	public HashFunctionFactoryMock()
	{
		super(ValueType.STRING);
	}

	@Override
	public HashFunction<String> getHashFunction(byte hashAlgorithm)
	{
		switch (hashAlgorithm)
		{
		case _BYTE:
		case _SHORT:
			return new HashFunction<String>()
			{
				@Override
				public int calculate(String key)
				{
					/*
					 * Note that the provided key should be a valid value from
					 * the enum.
					 */
					return ValueForMock.valueOf(key).ordinal() % INITIAL_SLOT_COUNT;
				}

				@Override
				public int maxValue()
				{
					return INITIAL_SLOT_COUNT;
				}
			};
		case _INT:
			return new HashFunction<String>()
			{
				@Override
				public int calculate(String key)
				{
					return ValueForMock.valueOf(key).ordinal();
				}

				@Override
				public int maxValue()
				{
					return ValueForMock.values().length;
				}
			};
		default:
			throw new CorruptedStorageException("Corrupted index");
		}
	}
}
